6 hour drive to visit my folks. So you know what I did? That's right. 6 more hours of live Grateful Dead. Tidal to FM transmitter deal via Bluetooth and then to truck radio. What an age we live in.
Completed 6 straight hours of live Grateful Dead from the Europe 1972 tour on Tidal and it still wasn't enough. Seriously good solos by Jerry in this version of Goin' down the road feelin' bad.
The service manual is in the database. it will list the values of those resistors;
https://thecarversite.com/manuals/mandir/Carver HR-722 service manual.pdf
Welcome to the forum. My first thought would be a dirty input level potentiometer. You could try spraying the pot with some fader lube and rotating the input level knob several times. See if that gets rid of the static.
If you have cleaned the volume pot and it still crackles or you have channel drop out you probably need to clean the balance pot. I am no expert, but I use fader lube on pots and contact cleaner on switches. Both caig deoxit.